Hello, My iphone 3GS works perfectly without inserting a SIM card in it and making calls but when i insert my sim and attempt a call it shuts of on its self and i have to turn it on back.
And when i turn it on it shows the apple logo and re shuts down and wont boot until i remove my sim card but it boots when it's on charge and make calls also please help i bought it brand new.
Why don't you ask the place you bought it from?
BTW you can change the SIM card while it's on.
i know i can change the sim but when i try to attempt a call it turns of and the store cant return it cz theres no apple store in lebanon i asked him he start saying that i dropped it or its maybe broken. i payed 600$ :( any solution? and even if i put any sim card mtc or alfa or any one and try to attempt a call it shuts down fast
Where did you get it from? If it's an unlocked phone, maybe someone knows someone who works with iPhones. I know Joe Cell in Ashrafieh. Such places may be able to flash it again, reset, whatever... so it gets working.
mmmm i got it from Cola in beirut mmm hadi cell. mmmm maybe it will work let me give a shot plz give me the store number or where is it in details :)
I found him on waseet

Joe Cell | Email
Hikme highway , Beirut, Achrafieh
Next To: Medco station

Tel: +961 1333633

http://www.waseet.net/lb/directory/details/3563/Joe-Cell&lang=EN

I know him because I found him on waseet about 1.5 years ago and bought an iphone 3G from there back then. But anyone like him who has knowledge and experience with unlocking the iPhone may be able to help you. He may of course charge a little, but maybe if he's honest he will not ask money if it doesn't work. Anyway good luck!
Which iOS version are you using ?

I'm guessing it's a problem from a cydia application you installed.